More Air PSI..or Less PSI? Winter driving?

[SubeeTed]

Hi all!

I have a '97 Legacy GT Wgn, it has those big 16 " tires. I have a set of Goodyear Assurance Triple treads. I have a simple...almost stupid question about traction on Snowy Days. This car has NO problems getting to go...the only problem is....ah....stopping! I still have somewhat of a lead foot in the winter also! I'm running 37 PSI up front, and 35 PSI in the rear, basically 5 PSI OVER the door sticker. I did this to improve my gas milage. Now it's winter...should I leave it the way it is? OR bring it back to 32/30. With the thinking that the less PSI makes a larger "Foot Print" and helps slow one down, or does it only hurt, because that big wide tire does even more hard hydoplaning (snow) ?

 

Thanks, SubeeTed

[Petersubaru]

Hi all!

I have a '97 Legacy GT Wgn, it has those big 16 " tires. I have a set of Goodyear Assurance Triple treads. I have a simple...almost stupid question about traction on Snowy Days. This car has NO problems getting to go...the only problem is....ah....stopping! I still have somewhat of a lead foot in the winter also! I'm running 37 PSI up front, and 35 PSI in the rear, basically 5 PSI OVER the door sticker. I did this to improve my gas milage. Now it's winter...should I leave it the way it is? OR bring it back to 32/30. With the thinking that the less PSI makes a larger "Foot Print" and helps slow one down, or does it only hurt, because that big wide tire does even more hard hydoplaning (snow) ?

 

Thanks, SubeeTed

bring the pressure down to what the door label specifies..then experiment by stopping..you should feel a difference

[idosubaru]

i bet it depends on a number of things, like exactly what kind of snow you're driving in too. i think there are instances where higher psi is better and i'd probably keep it there.

 

frankly though psi is a really weak way to *improve* snow traction, i'd guess the differences are extremely small. get studded tires if you insist on driving "with a lead foot" in the snow.

[nipper]

And be aware that tire pressure changes with air temperitures.

 

 

nipper

 

Every ten degree temp in air pressure you loose 1 psi of tire pressure. You are mor apt to see a temp change from 40 to zero where you live then to see an elevation change in your driveway.

 

Besides on a long trip you should be cheking your tire pressure anyway, like i know we all do.

 

Dont we?

 

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73

 

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=167

Edited December 22, 2008 by Qman

[heartless]

And be aware that tire pressure changes with air temperitures.

 

 

nipper

 

not so much ambient temperature but barometric pressure...

[CaptEditor]

We get a lot of snow pack here since the roads are rarely plowed. I actually preffer the fresh snow for stopping and if I am sliding, getting into the snow on the edges of the road can help slow me down. The biggest key is just to drive slower and leve much much larger following distances. Use the larger distance to take more time slowing down with less braking.

 

I know our cars can accelerate and handle well in the snow (as can many other vehicles), but the limiting factor always comes down to brakes.

[Qman]

Hi all!

I have a '97 Legacy GT Wgn, it has those big 16 " tires. I have a set of Goodyear Assurance Triple treads. I have a simple...almost stupid question about traction on Snowy Days. This car has NO problems getting to go...the only problem is....ah....stopping! I still have somewhat of a lead foot in the winter also! I'm running 37 PSI up front, and 35 PSI in the rear, basically 5 PSI OVER the door sticker. I did this to improve my gas milage. Now it's winter...should I leave it the way it is? OR bring it back to 32/30. With the thinking that the less PSI makes a larger "Foot Print" and helps slow one down, or does it only hurt, because that big wide tire does even more hard hydoplaning (snow) ?

 

Thanks, SubeeTed

 

The answer is YES! Lower air pressure will aid in traction. It allows the tire to be more pliable and it will grip better. I can lower the air pressure in my 2wd Suburban and get any where that a 4WD rig can go in the snow. I did this exact thing on Friday when we had compact snow and ice on all of our roads. Worked wonderfully and got me home without issue.I dropped mine in half. I would suggest that you go to 25psi.

[hankosolder2]

I'm going to say higher tire pressure is better. Reason is that as the tire is inflated more, the center of the tread contacts more and the edges contact less. It's effectively kind of like going to a more narrow tire. (Narrower tires do much better in the snow because the smaller contact patch allows the snow, water, etc to be displaced easily to the edge.)

 

It might depend on the kind of snow, and obviously, some seem to disagree with my conclusions. I noticed a meaningful difference today in a FWD Honda increasing to max permitted sidewall pressure.

 

Nathan

[ferret]

Depends on the tire ........

 

Snow tire ( Non directional ) with lugs on the edges, lowering the pressure will lift the pressure from the center of the tread and put more on the edges. So you may gain more traction especially in softer uneven snow. It also makes your tread patch smaller since the center now has less pressure, so on flat smooth roads, you traction is lessened and tire wear is greater.

 

Directional Snow tires work best at the recommended pressure as this allows the center groves to have the proper pressure and clear themselves toward the outer edges. The outer edges alone on these tires were not designed to clear themselves without the inner flat on the ground.

[edrach]

Just a comment on lower pressures. Less PSI can allow moisture to get into the tire's bead and when that freezes will expand and give you a flat tire. That being said, here's my suggestion:

 

Don't screw with summer tires in the winter. Buy a cheap set of junkyard wheels for your car and get a set of decent studless or studded snow tires (I prefer studless here in the Seattle area). Initial cost is an issue, but over the long run, the only extra cost is the wheels and mounting, since for every mile you run on your winter tires, you'll get another mile of use out of your summer tires.

[zyewdall]

Don't screw with summer tires in the winter. Buy a cheap set of junkyard wheels for your car and get a set of decent studless or studded snow tires

 

yeah... if you are in a location where you expect to be driving on the snow more than a few times a winter (I'm on snow or ice of some sort for at least part of my commute for 4 to 7 days a week for about 5 months a year). I switched from Michelin Harmony to studded Hankook Ipike for the winter... and it's a world of difference. I run both of them at 40psi. With the Ipikes I can floor it and not spin out (75HP yeah:rolleyes:), or stomp on the brakes... and start skidding... studded snow tires only go so far But it does skid in a very straight line, and you really have to try to get it to skid, unlike the harmony's which touching the brake more than very gently would start locking up some tires when on packed ice.